In modern Aerospace Engineering, the certification of the primary structure of an airplane is done by testing validation at different structure levels. Testing subcomponents like panels allow finding out possible local failures that can be solved before mounting the component. The use of skin panels, specially carbon fiber reinforced panels, leads to their previous testing under several conditions: pure compression, pure shear and combined compression-shear.
In the prior art, there are known the following two methods to apply combined shear-compression actions on panels.
One method uses a box subjected to bending and torsion in which the panel to be tested is introduced. This method, called “four point bending test”, applies (see FIGS. 1 and 2) combined shear 2 and compression 3 actions on a panel 1. It use a box 4 subjected to bending and torsion in which the panel 1 to be tested is mounted. The panel 1 is then subjected to combined shear-torsion loads by means of hydraulic jacks 5.
The main problem of this method is the high cost and the long duration of the whole process, being necessary the manufacturing of a new box for each new test or panel. Besides, in most of the cases, one new box 4 is required for each tested panel 1, because it is very difficult to prevent the damage of said box 4 when the failure of the panel 1 occurs.
Another method uses a special machine to test panels, in which each action (see FIG. 3) compression 7 and shear 8, is applied separately on each tested panel 1 by means of hydraulic actuators 6.
The main disadvantage of this method is that very expensive machines with complex hydraulic and test control systems are necessary. Moreover, these machines are only valid for this kind of tests.
The present invention provides an assembly for testing panels, and in particular skin panels for aircraft surfaces, under combined shear-compression loads, and a method for testing panels using said assembly, that comes to solve previous limitations in the known art.